var dateFormat = function () {
        var	token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g,
                timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g,
                timezoneClip = /[^-+\dA-Z]/g,
                pad = function (val, len) {
                        val = String(val);
                        len = len || 2;
                        while (val.length < len) val = "0" + val;
                        return val;
                };

        // Regexes and supporting functions are cached through closure
        return function (date, mask, utc) {
                var dF = dateFormat;

                // You can't provide utc if you skip other args (use the "UTC:" mask prefix)
                if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/\d/.test(date)) {
                        mask = date;
                        date = undefined;
                }

                // Passing date through Date applies Date.parse, if necessary
                date = date ? new Date(date) : new Date;
                if (isNaN(date)) throw SyntaxError("invalid date");

                mask = String(dF.masks[mask] || mask || dF.masks["default"]);

                // Allow setting the utc argument via the mask
                if (mask.slice(0, 4) == "UTC:") {
                        mask = mask.slice(4);
                        utc = true;
                }

                var	_ = utc ? "getUTC" : "get",
                        d = date[_ + "Date"](),
                        D = date[_ + "Day"](),
                        m = date[_ + "Month"](),
                        y = date[_ + "FullYear"](),
                        H = date[_ + "Hours"](),
                        M = date[_ + "Minutes"](),
                        s = date[_ + "Seconds"](),
                        L = date[_ + "Milliseconds"](),
                        o = utc ? 0 : date.getTimezoneOffset(),
                        flags = {
                                d:    d,
                                dd:   pad(d),
                                ddd:  dF.i18n.dayNames[D],
                                dddd: dF.i18n.dayNames[D + 7],
                                m:    m + 1,
                                mm:   pad(m + 1),
                                mmm:  dF.i18n.monthNames[m],
                                mmmm: dF.i18n.monthNames[m + 12],
                                yy:   String(y).slice(2),
                                yyyy: y,
                                h:    H % 12 || 12,
                                hh:   pad(H % 12 || 12),
                                H:    H,
                                HH:   pad(H),
                                M:    M,
                                MM:   pad(M),
                                s:    s,
                                ss:   pad(s),
                                l:    pad(L, 3),
                                L:    pad(L > 99 ? Math.round(L / 10) : L),
                                t:    H < 12 ? "a"  : "p",
                                tt:   H < 12 ? "am" : "pm",
                                T:    H < 12 ? "A"  : "P",
                                TT:   H < 12 ? "AM" : "PM",
                                Z:    utc ? "UTC" : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""),
                                o:    (o > 0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),
                                S:    ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10]
                        };

                return mask.replace(token, function ($0) {
                        return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1);
                });
        };
}();

// Some common format strings
dateFormat.masks = {
        "default":      "ddd mmm dd yyyy HH:MM:ss",
        shortDate:      "m/d/yy",
        mediumDate:     "mmm d, yyyy",
        longDate:       "mmmm d, yyyy",
        fullDate:       "dddd, mmmm d, yyyy",
        shortTime:      "h:MM TT",
        mediumTime:     "h:MM:ss TT",
        longTime:       "h:MM:ss TT Z",
        isoDate:        "yyyy-mm-dd",
        isoTime:        "HH:MM:ss",
        isoDateTime:    "yyyy-mm-dd'T'HH:MM:ss",
        isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'"
};

// Internationalization strings
dateFormat.i18n = {
        dayNames: [
                "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
                "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
        ],
        monthNames: [
                "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
                "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"
        ]
};

// For convenience...
Date.prototype.format = function (mask, utc) {
        return dateFormat(this, mask, utc);
};
